Modeling the Metal–Insulator Phase Transition in Li_xCoO₂ for Energy and Information Storage

An electro-chemomechanical phase-field model is developed to capture the metal–insulator phase transformation along with the structural and chemical changes that occur in Li_xCoO₂ in the regular operating range of 0.5 < x < 1. Under equilibrium, in the regime of phase coexistence, it is found that transport limitations lead to kinetically arrested states that are not determined by strain-energy minimization. Further, lithiation profiles are obtained for different discharging rates and the experimentally observed voltage plateau is observed. Finally, a simple model is developed to account for the conductivity changes for a polycrystalline Li_xCoO₂ thin film as it transforms from the metallic phase to the insulating phase and a strategy is outlined for memristor design. The theory can therefore be used for modeling Li_xCoO₂-electrode batteries as well as low voltage nonvolatile redox transistors for neuromorphic computing architectures.